and Duke of Burgundy, together with comparatively large populations of brown argus, green hairstreak, chalkhill blue, marbled white and dingy skipper. Geology Structure The structural picture is similar to that at Winchester to the west, with an east–west trending anticline in the upper chalk (the Winchester-East Meon Anticline) cut through by a south-flowing river to expose an inlier of middle and lower chalk. As with the Itchen, the upper Meon flows westwards along the fold trend, before swinging south to cut through the anticline. Beacon Hill at to the west of the Meon and Old Winchester Hill at to the east are remnants of the southward-dipping chalk on the southern side of the anticline. The anticline is somewhat domed, with the result that Old Winchester Hill is capped by older chalk than Beacon Hill despite being rather higher, whilst Wether Down and Butser Hill to the east are higher still. Geomorphology Beacon Hill is a section of east-facing Upper Chalk escarpment. Both Beacon Hill and Old Winchester Hill have a claim to being the point at which the main north-facing scarp of the South Downs turns northwards around the western end of the Weald; Beacon Hill is lower, but represents a higher level within the chalk, and Old Winchester Hill is cut to the north by the upper Meon valley. Small suggests that the upper Meon (which like the upper Itchen flows east–west) was originally a headwater of the Itchen following the col to the north of Beacon Hill, before the south-flowing lower Meon cut back through the chalk. The hill has been incised by a series of steep-sided semi-circular combes to the east, and deep dry valleys to the south and west. Between these several radiating spurs with minor roads and tracks meet near the summit. External links United Kingdom Butterfly Monitoring Scheme Natural England - SSSI Unit 1 - Woodland Natural England - SSSI Unit 3 - Calcareous grassland References National nature reserves in England Nature Conservation Review sites Sites of Special Scientific Interest in Hampshire Hills of Hampshire Late Neolithic